In medicinal technology, such .as technology involving medicinal equipment such as devices for implantation or apparatus exposed to living tissue, it is often desirable to make the exposed surfaces compatible with the environment. This is often done by immobilizing biologically active compounds onto the exposed surfaces. This is usually made in two steps, viz. a first step of activating the surface in question and a second step of coupling the biologically active compound to the activated surface.
In the first step residing in activation which frequently takes place by the treatment using a polymeric compound, the introduced reactive and functional groups should be attached to the substrate by strong binding thereto. In the second step residing in the coupling the binding shall also be as strong as possible. However, the biological activity of the immobilized substance must not be impaired.
As examples of techniques for the immobilization of a biologically active compound onto the surface of for example hospital equipment are the immobilization of glycoseaminoglycans (GAGs) on intraocular eye lenses, certain wound dressings, orthopedic implants etc. Such immobilization of GAGs is usually performed in two steps, namely pretreatment of the surface to make it more reactive and/or hydrophilic, and immobilization of the molecule by ionic or covalent binding. In such pretreatment procedure a reagent or primer containing reactive amino functions is adhered to the surface. This reagent can be further stabilized by the addition of a crosslinking agent, usually by a functional organic substance.